As conventional files, for example, a file which has a binding string coated with synthetic resin with flexibility but little expandability and a double row of ribbing erected on the upper surface of a band-shaped board (Japanese Utility Model Laid-Open Publication No. 62-162070), a file comprising a box unit with a cut out for drawers and a bottom plate having a receiving part for fitting, a pressing tool with a U-shaped cross-section, and a stopper tool with a protrusion part for fitting which is fitted onto the receiving part for fitting of the box unit (Japanese Utility Model Laid-Open Publication No. 54-151420), and a file composed of a file front cover, and a band-shaped component comprising a locking part and a locked part (Japanese Utility Model Laid-Open Publication 60-192696), for example, are proposed as conventional files.
All of these proposals comprise conventional filing functions, and considerations towards response to environmental protection are partially made.
Although Japanese Utility Model Laid-Open Publication No. 62-162070 is advantageous in that there are few number of parts, metal parts are not required, and the construction is simple, because there are two binding string holes for holding the file, the load applied to each hole is large, the sheet cannot be secured stably, and it may be insufficient in terms of function when a sheet such as a clear file is attached.
In addition, Japanese Utility Model Laid-Open Publication No. 54-151420 does not require metal parts, comprises a plurality of holes in terms of functionality, and therefore, sheets and the like can be held steadily. On the other hand, as the number of parts increase, attachment and removal becomes less than easy, and its structure is not necessarily simple.
Furthermore, Japanese Patent Laid-Open Publication 60-192696 has few number of parts, does not use metal parts, can hold sheets without fail with a simple structure, and insertion/removal and addition of sheets from in between are possible. However, because a folding-type band-shaped component folded from the top and bottom of the file, is used, there are problems in that exterior deterioration of the folding sections, such as whitening, occurs more easily and it weakens in terms of strength, as well.
Therefore, the present invention provides a simply structured file which facilitates the attachment and removal of sheets having binding holes, wherein, in order to function sufficiently as a file, sheets can be held without fail, insertion/removal and addition in between are facilitated, it is convenient, and furthermore, there are few number of parts and not many types of materials.